Then 10 dusk still shots + 430EXII while Live View on, but reviewing results & deleting unwanted with Live View off between shots. Turned Live View off when finished.

Got home, pressed shutter half down to activate & review images again, got some kind of "cannot playback" message on back panel with big "?" question mark.
All dusk shots (did not delete 3) were gone, all daytime shots were OK.
(did not take CF card out, battery was charged at all times)
(took test Live View still shot at home & it did not disappear)